According to a NIDR survey on employed American adult's oral health, approximately 42% of those older than 65 years and 4% of those 35 to 65 years are totally edentulous. Additionally, by the age of 65, those with teeth have lost an average of ten, while those between the ages of 55 to 64 have lost nine. This tremendous number of individuals could benefit from dental implant therapy. Following tooth extraction, the edentulous ridge begins to resorb thus reducing the bone available for implant therapy. Implant placement at the time of tooth loss or immediately there after may allow early restoration and preserve remaining bone. The proposed endosseous implants use proven masonry fastener technology to adjust their outer diameter, allowing them to contact bone from crest to apex of a drilled bone defect or in an extraction site. This mechanism will provide initial implant stability and allow for subsequent integration. This technology allows the physician to place an implant in a delayed immediate surgical procedure or immediately following tooth extraction. This technology is anticipated to protect alveolar bone, require less surgical manipulation, provide more stable fixation, allow more aesthetic restoration and can be removed upon failure or disease. PROPOSED COMMERCIAL APPLICATION: The Med-U-Lock endosseous implant was designed with procedural and clinical simplicity to encourage rapid sales growth, broad practitioner acceptance and reduction in procedural cost. It is expected that the Med-U-Lock implant will encourage implant use by general dentists (increasing the practitioner base from 17,000 up to as many as 164,000 and a patient base form 2.5 million up to a total of 125 million.) Market projections predict that if the Med-U-Lock captures one percent of the present market and had modest growth (5% gross revenue), sales will exceed $15 million by 1999.